Table 2.

Impact of preanalytical sample handling conditions on metabolite abundances.

	Absolute Percent Difference (APD)				Normalized Difference (ND)
	With Preservative		Without Preservative		With Preservative		Without Preservative
	median	IQR	median	IQR	median	IQR	median	IQR
Preservative
None (Gold Std. Duplicates)	3.57	(1.5–7.45)
Borate	2.95	(1.06–8.60)			0.023	(0.010–0.075)
Chlorhexidine	3.00	(1.16–7.31)			0.022	(0.006–0.057)
Refrigeration	2.40	(0.91–4.92)	3.01	(1.22–7.74)	0.025	(0.01–0.049)	0.044	(0.016–0.088)
Thaw
1 thaw
On ice	1.65	(0.65–3.56)	3.13	(1.29–6.69)	0.015	(0.006–0.034)	0.027	(0.011–0.056)
In refrigerator	2.61	(1.11–5.74)	3.75	(1.46–8.73)	0.021	(0.008–0.040)	0.032	(0.014–0.064)
At room temp.	2.13	(0.89– 4.53)	4.00	(1.5–9.47)	0.021	(0.010– 0.044)	0.0 34	(0.012– 0.083)
4 thaws
On ice	3.79	(1.86–6.41)	5.31	(2.53–9.03)	0.035	(0.019–0.063)	0.041	(0.020–0.074)
In refrigerator	2.39	(0.94–5.61)	4.18	(1.79–8.88)	0.014	(0.005–0.033)	0.021	(0.008–0.051)
At room temp.	2.41	(0.96–4.73)	3.85	(1.7–8.07)	0.017	(0.006–0.040)	0.025	(0.011–0.057)